EP3390673B1 - Method for the manufacture of semi-finished products of leather or fur - Google Patents

Description

The present invention relates to a process for the production of semi-finished leather or fur products using the condensation product of component a), the semi-finished leather or fur products produced therefrom, a mixture containing the condensation product of component a) and their use for treating hides or skins, and processes for the production of leather or fur using the leather or fur semi-finished products obtained by the process according to the invention, also using the mixture containing the condensation product of component a), and the leather and fur obtained.

Condensation products whose structural units are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde are known in principle and, for example, in Ullmann's encyclopedia of technical chemistry (volume 16, 1978, pp. 138-140 ) described. Their use in tanning processes is also described, for example in EP 1416058 A1 or in EP 459168 A2 . In the latter and in many processes known from the literature, semi-finished products that have already been metal-tanned, preferably chrome-tanned (referred to as "wet blue" in the case of chrome tanning), are usually used, with the condensation products only being used in a retanning (i.e. the after-treatment of the already tanned leather or Furs) are used to optimize the haptic and optical properties of the leather or fur that has already been tanned, for example in terms of colour, fullness, softness and levelness. In the application processes described above, the condensation products do not develop any tanning function, since semi-finished products that have already been tanned are used as substrates.

Leather production using chromium-containing tanning agents is the dominant tanning method, e.g. in the production of shoe upper leather. After proper tanning, the tanned leather should only contain chromium compounds with chromium in the oxidation state (III) that are classified as not hazardous to health. Improper tanning or insufficient post-treatment of the leather with strongly oxidizing chemicals can, however, result in highly toxic chromium compounds with chromium in the oxidation state (VI).

Therefore, a tanning process based on metal-free tanning is desirable.

There is a great demand for metal-free tanned leather, particularly in the area of automotive leather production. The standard process for producing metal-free tanned leather is based on the use of metal-free semi-finished products instead of wet blue. These semi-finished products, which are also known as wet white leather, can be obtained, for example, by treating the hides or skins with glutardialdehyde.

In the classic tanning process, hides or skins are subjected to pickling before tanning. The process step of pickling means a treatment step of the material to be tanned before tanning, in which the skin material to be tanned is prepared for tanning in the acidic pH range and to avoid acid swelling with the help of strong acids and salt, preferably with a mixture containing formic acid and/or sulfuric acid in the presence of sodium chloride, the pH of the aqueous tanning liquor being adjusted to 2 to 3.5. This preferably ensures that the tanning agent used penetrates the skin better.

DE10140551A1 discloses a polycondensation product of 4,4'-dihydroxydiphenyl sulfone, the sodium salt of p-phenol sulfonic acid and aqueous formaldehyde solution mixed with a tanning agent based on sulfonated phenol/urea/formaldehyde resin for tanning pickled cattle pelts at a pH between 3 and 4.

The pimple has a number of disadvantages: the use of sodium chloride involves a high salt load in the wastewater and a high water requirement, which is cost-intensive and harmful to the environment. Furthermore, the pimple is an additional work step that has an unfavorable effect on costs. In addition, the adjustment of the pH requires careful control and thus means an additional outlay on the process. Due to the low pH value, the skin material can also be damaged by hydrolysis of the collagen, resulting in negative effects on the leather to be produced.

Therefore, a tanning process that does not require the prior pickling step is desirable.

From the registration WO 2010130311A1 a tanning process is known which, in a preferred embodiment, also discloses a pimple-free implementation of a tanning process. The tanning substance in this process meets the criteria of an aromatic amine and a reactive organic halogen compound. Diarylamines are often carcinogenic or suspected of being carcinogenic. Another disadvantage of this process is that the presence of absorbable organic halogen (AOX) in the wastewater cannot be completely ruled out. The presence of chloride ions in this tanning process can damage machine parts through corrosion.

From the WO 2012136565A1 polycarbamoylsulfonate-containing tanning agents are known which do not have the disadvantages mentioned above.

The object of the present invention was to provide a process for the production of semi-finished leather or fur products which overcomes the disadvantages mentioned in the prior art. The process should preferably be a process for the production of metal-free tanned leather or fur semi-finished products, i.e. wet white leathers or furs. Furthermore, it was the aim of the present invention that the process preferably dispenses with the process step of pickling. In addition, it was an aim that the process leads to semi-finished leather or fur products, preferably wet white leathers or furs, which are preferably characterized by a high shrinkage temperature. It was also desirable to provide a simplified tanning process without corrections during processing, a shorter running time for the overall process, and effective control of the penetration of the tanning agent using an indicator.

Surprisingly, it was found that the use of the condensation product of component a) in processes for treating hides or skins, in particular pelts, leads to semi-finished leather or fur products, preferably wet-white leathers or furs, which are characterized by high shrinkage temperatures, Softness, fullness, resilience, absence of grain and great advantages in mechanical processing, e.g. improved processing behavior during wilting (mechanical drainage) and folding (thickness regulation). In addition, the process step of pickling is preferably dispensed with in the process according to the invention. In addition, the method according to the invention has a simplified tanning process without corrections during processing, a shorter running time for the overall method, and effective monitoring of the penetration of the tanning agent by means of an indicator.

The invention therefore relates to a process for the production of leather or fur semi-finished products, characterized in that hides or skins in the presence of a condensation product of component a), the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde, at a pH of 6 .5-8.5, preferably 7-8, are treated.

In the context of this application, "skins or pelts" is understood to mean an animal skin or pelt that is obtained according to the steps that are customary for the water workshop and known to the person skilled in the art, such as fleshing, splitting, deliming, and which has not previously been obtained has been subjected to tanning.

In the context of this application, "pelt material" is understood to mean an animal skin that is dehaired and obtained by the steps known to those skilled in the art such as dehairing, fleshing, splitting, deliming, and which has not yet been subjected to tanning has been.

In the context of this application, "pelt weight" is understood to mean the weight of the hide or hide or semi-finished product used in the tanning or retanning process.

"Treatment of skins or skins, in particular pelt material," means in the context of this application the treatment of skins or skins, in particular pelt material, with a tanning agent for the production of semi-finished leather or fur products, the shrinkage temperature of the tanned skin or skin material during tanning, so that at least hydrothermal stabilization of the hide or skin material is achieved, which allows subsequent processing by mechanical operations and avoids damage from mechanical and thermal stress (frictional heat during folding).

In the context of this application, “tanning agent” means that this substance leads to an increase in the shrinkage temperature when used to treat hides or skins, in particular pelt material.

In the context of this application, "semi-finished leather or fur products" are leather or fur intermediate products obtained from skins or skins, in particular pelt material, and the shrinkage temperature of which is so high that at least hydrothermal stabilization of the skin material is achieved which allows subsequent processing by mechanical operations and avoids damage from mechanical and thermal stress (frictional heat during folding). Such semi-finished leather or fur products have not yet been retanned to optimize their haptic and visual properties.

In the context of this application, "wet white leather" or "wet white fur" is understood to mean leather or fur semi-finished products which were obtained from hides or skins tanned without metal, in particular hides or skins tanned without chrome.

In the context of this application, “wet blue leather” or “wet blue fur” is understood to mean semi-finished leather or fur products which were obtained from metal-tanned hides or skins, in particular chrome-tanned hides or skins.

In the context of this application, “leather” or “fur” is understood to mean leather or fur that, after retanning semi-finished leather or fur products with other substances, is used to optimize the haptic and visual properties, for example with regard to color , Fullness, Softness and Equality.

In a preferred embodiment, the method according to the invention is a method for producing wet white leathers and furs.

In a preferred embodiment, the hides or skins used in the method according to the invention are pelt material.

In a further preferred embodiment, the process according to the invention is a process for the production of semi-finished leather or fur products which takes place without the process step of pickling.

In the context of this application, the "pickling" process step is understood to mean the treatment step before the treatment of hides or skins with a tanning agent, in which the hides or skins are treated with an aqueous solution containing acid and salt, which has a pH of 2 -3.5. The acid can be organic or inorganic. The acid is preferably at least one acid selected from the group consisting of formic acid, hydrochloric acid and sulfuric acid, particularly preferably consisting of formic acid and sulfuric acid. The salt is preferably sodium chloride.

The pH value in the method according to the invention can be adjusted to a pH value of 6.5-8.5, preferably to a pH value of 7-8 , to be set.

The pH in the process according to the invention can also be adjusted to a pH of 6.5-8.5, preferably 7, before, during and after the addition of the condensation product of component a) by adding buffer substances, acids, bases or other additives - 8, to be adjusted. A preferred pH-adjusting additive is ammonium sulfate.

The pH in the process according to the invention is preferably adjusted to a pH of 6.5-8.5, preferably 7-8, by adding the condensation product of component a).

In this preferred embodiment of the process according to the invention, the pH value does not need to be corrected by further additives.

component a)

According to the invention, the structural units of the condensation product of component a) are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde.

In a preferred embodiment, the structural units of the condensation product of component a) are derived from phenolsulfonic acid, 4,4'- and/or 2,4'-dihydroxydiphenylsulfone, particularly preferably 4,4'- and 2,4'-dihydroxydiphenylsulfone, and Formaldehyde.

The structural units of the condensation product of component a) derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde are preferably in a ratio of 1:(1-10):(1.4-7.7), preferably 1:(1-5): (1.4-4.2), more preferably 1:(2-4):(2.1-3.5).

Condensation products of component a) are preferably prepared by polycondensation of phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde in the presence of sodium hydroxide solution.

Furthermore, it is also possible to add a reducing agent such as sodium hydroxymethanesulfinate to the reaction mixture after the condensation reaction, which is subsequently also present in the condensation product of component a).

In an alternative embodiment, the condensation product of component a) is understood to mean that it also contains sodium hydroxymethanesulfinate in addition to the condensation product whose structural units are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde. Sodium hydroxymethanesulfinate is commercially available, for example under the name Rongalit ^C® from BASF.

After its preparation, the condensation product of component a) can be present in an aqueous solution. In the method according to the invention, this solution can be added directly to the skin or the fur, in particular the pelt material.

Alternatively, it is also possible to add spray drying to the above-described production process for the condensation product of component a) and to obtain the condensation product of component a) as a solid, preferably as a pulverulent solid.

In the process according to the invention, the condensation product of component a) can be used as a solid or present in an aqueous solution.

The condensation product of component a) is preferably used in an aqueous solution in the process according to the invention.

The aqueous solution of the condensation product of component a) can also contain organic additives. Suitable organic additives are those which are soluble in water, for example ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and polyethers based on ethylene oxide or on ethylene oxide and propylene oxide, such as alpha,omega-dihydroxypoly(oxyethylene) or alpha,omega-dihydroxypoly (oxyethylene-co-oxypropylene) with a molar mass of 200 to 10000 g/mol, pyrrolidinone, N-(C ₁ -C ₃ )alkylpyrrolidinone, acetone, aliphatic alcohols such as ethanol, propanol, isopropanol and diethanolamine.

The aqueous solution of the condensation product of component a) preferably has a solids content of 5-50% by weight, particularly preferably 8-35% by weight, very particularly preferably 15-30% by weight (percent by weight), the % by weight are based on the weight of the aqueous solution.

The solids content of the aqueous solution of the condensation product of component a) is understood as meaning the content of solids that is present when the water has been removed from the aqueous solution of the condensation product of component a). This can be done, for example, by means of spray drying.

If the condensation product of component a) is used in an aqueous solution in the process according to the invention, it is preferably used in an amount of 10-100% by weight, particularly preferably 15 to 50% by weight, very particularly preferably 20-30% by weight. -%, based on the pelt weight, used.

In a further preferred embodiment of the process according to the invention, the condensation product of component a) is added as a solid.

The condensation product of component a) in the process according to the invention is preferably added in an amount of from 2 to 8% by weight, particularly preferably from 3 to 6% by weight, based on the weight of the pelt.

In a preferred embodiment, a salt of the condensation product of component a) is used in the process according to the invention, particularly preferably an alkali metal salt, very particularly preferably a sodium salt.

component b)

In addition to the condensation product of component a), at least one organic tanning assistant of component b), which is different from the condensation product of component a), may or may not be present in the process according to the invention for the production of semi-finished leather or fur products.

In the context of this application, “organic tanning agent” means that this substance, which is an organic tanning agent per se, is used in the context of this application before, together with or after the condensation product of component a) in the process according to the invention.

The at least one organic tanning agent of component b) is preferably selected from the group consisting of b1) at least one compound containing carbamoylsulfonate groups, b2) syntans, b3) resin tanning agents and b4) vegetable tanning agents.

The at least one organic tanning assistant of component b) is particularly preferably at least one compound of component b1) containing carbamoylsulfonate groups.

In a preferred embodiment of the process according to the invention, the condensation product of component a) and the at least one organic tanning assistant of component b) are present in a ratio of 99:1 to 50:50, preferably in a ratio of 95:5 to 70:30.

component b1)

In the context of this application, a compound of component b1) containing carbamoylsulfonate groups is understood as meaning compounds having the following structural unit:

-NH-CO-SO ₃ -K ⁺

where K ⁺ is a cation equivalent.

Suitable compounds of component b1) containing carbamoylsulfonate groups are preferably reaction products of at least one organic polyisocyanate and at least one bisulfite and/or disulfite.

Suitable organic polyisocyanates are, in particular, aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic polyisocyanates, as described, for example, by W. Siefken in Liebigs Annalen der Chemie 562, pages 75 to 136.

Organic polyisocyanates with an NCO functionality of 1.8 to 4.2 and a molar mass of preferably below 800 g/mol are preferred, in particular organic polyisocyanates with an NCO functionality of 1.8 to 2.5 and a molar mass below 400 g /mol .

können verwendet werden.Particularly preferred polyisocyanates are those with a molecular weight of less than 400 g/mol with NCO groups bonded to aliphatics or cycloaliphatics, such as 1,4-diisocyanatobutane, 1,6-diisocyanatohexane (HDI), 1,5-diisocyanato-2, 2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane (TMHI), 1,3- and 1,4-diisocyanatohexane, 1,3- and 1,4-diisocyanato -cyclohexane (CHDI) and any mixtures of these isomers, 1-isocyanato-2-isocyanatomethyl-cyclopentane, 1,2-, 1,3- and 1,4-bis(isocyanatomethyl)-cyclohexane and any mixtures of isomers, 1,2 -, 1,3- and 1,4-bis(isocyanatoethyl)cyclohexane and any mixtures of these isomers, 1,2-, 1,3- and 1,4-bis(isocyanato-n-propyl)cyclohexane and any mixtures of these isomers, 1-isocyanatopropyl-4-isocyanatomethyl-cyclohexane and isomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane (IPDI), 1-isocyanato-1-methyl-4-isocyanatomethyl-cyclohexane (IMCI), 2,4'- and 4,4 '-Diisocyanatodicyclohexylmethane (H ₁₂ MDI) and isomers, dimeryl diisocyanate (DDI), bis(isocyanatomethyl)bicyclo[2.2.1]heptane (NBDI), bis(isocyanatomethyl)tricyclo[5.2.1.0 ^2.6 ] decane (TCDDI) and isomers and any mixtures of such diisocyanates. Also araliphatic polyisocyanates such as the xylylene diisocyanates of the formulas

can be used.

1,6-diisocyanatohexane (HDI) is very particularly preferred.

component b2)

1. A) Sulfonsäuregruppen und/ oder Carboxylgruppen- enthaltende Aromaten,
2. B) Aldehyden und/oder Ketonen und gegebenenfalls
3. C) einer oder mehreren Verbindungen, ausgewählt aus der Gruppe der nicht sulfonierten Aromaten, Harnstoff und Harnstoffderivaten,

verstanden, wobei die Syntane der Komponente b2) von dem Kondensationsprodukt der Komponente a) verschieden sind.In the context of this application, syntans of component b2) are condensation products based on

1. A) aromatics containing sulfonic acid groups and/or carboxyl groups,
2. B) aldehydes and/or ketones and optionally
3. C) one or more compounds selected from the group of non-sulfonated aromatics, urea and urea derivatives,

understood, wherein the syntans of component b2) are different from the condensation product of component a).

"On the basis of" means that the condensation product was optionally prepared from further reactants in addition to A, B and optionally C. Preferably, however, the syntans of component b2) are only prepared from A, B and, if appropriate, C in the context of this application.

In the context of this application, aromatics containing sulfonic acid groups (sulfonated aromatics) of component A) also include sulfomethylated aromatics. Examples of preferred sulfonated aromatics are naphthalenesulfonic acids, phenolsulfonic acid, sulfonated ditolyl ether, dihydroxydiphenylsulfone, sulfonated diphenylmethane, sulfonated diphenyl, sulfonated terphenyl, benzenesulfonic acids or toluenesulfonic acid.

Preferred carboxyl-containing aromatics of component A) are, for example, naphthalenecarboxylic acid, naphthalenedicarboxylic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, benzoic acid, phthalic acid, terephthalic acid, hydroxybenzoic acid, dihydroxybenzoic acid, trihydroxybenzoic acid, hydroxydicarboxybenzene, hydroxytricarboxybenzene, trimellitic acid, pyromellitic acid, carboxydiphenyl ether , dicarboxydiphenyl ether, carboxy-phenyl tolyl ether and dihydroxy-diphenyl ether.

Preferred aldehydes and/or ketones of component B) are aliphatic, cycloaliphatic and aromatic aldehydes and/or ketones. Aliphatic aldehydes are particularly preferred, formaldehyde and aliphatic aldehydes having 3 to 5 carbon atoms are very particularly preferred.

Preferred non-sulfonated aromatics of component C) are phenol, cresol, dihydroxydiphenyl ether and dihydroxydiphenylmethane.

Preferred urea derivatives of component C) are dimethylolurea, melamine, dicyandiamide and guanidine.

Phenol and phenol derivatives such as phenolsulfonic acid are often linked by the simultaneous action of formaldehyde and urea or by dimethylolurea ( DE-A 1 113 457 ). Sulfonation products of aromatic compounds are (according to Ullmann's Encyclopedia of Industrial Chemistry, Volume 16, 4th edition, Weinheim 1979, p. 138) usually condensed with formaldehyde alone or together with other starting compounds without separating off the unreacted starting compounds. In the case of phenols, a group which promotes solubility can also be introduced by sulfomethylation with the simultaneous action of alkali metal hydrogen sulfite and formaldehyde together with the condensation. This sulfomethylation is, for example, in DE-A 848 823 described.

Other preferred condensation products of component b2) are condensates built up from ditolyl ether sulfonic acid, 4,4'-dihydroxydiphenyl sulfone and/or 2,4'-dihydroxydiphenyl sulfone and their isomers, phenolsulfonic acid, phenol and, if appropriate, urea with formaldehyde.

Particularly preferred condensation products are those obtained by condensing aromatics which contain sulfonic acid groups and are optionally not sulfonated with aliphatic aldehydes, preferably formaldehyde.

Such condensation products are preferably obtained by condensation of sulfonated naphthalene and sulfonated phenol or dihydroxydiphenyl sulfone and their isomers with formaldehyde or by condensation of naphthalene sulfonic acid and formaldehyde or by condensation of sulfonated ditolyl ether, sulfonated phenol with formaldehyde or by condensation of sulfonated phenol, urea, phenol with formaldehyde or obtained by condensation of sulfonated phenol, urea, phenol, sulfonated ditolyl ether with formaldehyde.

The condensation product preferably obtained in the condensation preferably has an average degree of condensation of from 1 to 150, preferably from 1 to 20, in particular from 1 to 5.

Further preferred condensation products of component b2) are products based on the condensation of naphthalene sulfonic acids, ditolyl ether sulfonic acids, phenol sulfonic acids, dihydroxydiphenyl sulfone and phenol and combinations of these raw materials with formaldehyde or glutardialdehyde and optionally urea or urea derivatives.

Likewise suitable syntans of component b2) are polycondensates based on dihydroxydiphenyl sulfone/naphthalene sulfonic acid and formaldehyde, dihydroxydiphenyl sulfone/ditolyl ether sulfonic acid and formaldehyde, dihydroxydiphenyl sulfone/phenol sulfonic acid/ditolyl ether sulfonic acid/urea and formaldehyde, sulfomethylated dihydroxydiphenyl sulfone/urea and aldehydes, preferably formaldehyde, and sulfomethylated dihydroxydiphenyl sulfone/ Phenol / urea or urea derivatives and aldehydes, preferably formaldehyde, and mixtures thereof (commercial tanning agents such as TANIGAN ^® BN, TANIGAN ^® PR, TANIGAN ^® 3LN, TANIGAN ^® HO, TANIGAN ^® UW, from LANXESS, or mixtures thereof).

component b3)

1. i) Aldehyden, wobei der Aldehyd ausgewählt ist aus der Gruppe der Di-aldehyde der Gruppe C₂ bis C₁₂, und
2. ii) wenigstens einer NH₂-Gruppen tragenden Verbindung

verstanden, wobei die Kondensationsprodukte Säuregruppen enthalten und unter Säuregruppe Sulfon- und/oder Carbonsäuregruppen sowie deren Salze verstanden werden.In the context of this application, resin tanning agents of component b3) are condensation products based on

1. i) aldehydes, where the aldehyde is selected from the group of dialdehydes from the group C ₂ to C ₁₂ , and
2. ii) at least one compound bearing NH ₂ groups

understood, where the condensation products contain acid groups and acid groups are understood to mean sulfone and/or carboxylic acid groups and their salts.

"Based on" means that the resin tanning agent of component b3) is optionally prepared from further reactants in addition to i), ii) and optionally iii) acid group-introducing reactants.

Preferred dialdehydes of component i) are aliphatic or aromatic C ₂ -C ₁₂ dialdehydes. Aliphatic C ₂ -C ₁₂ -dialdehydes are particularly preferred, and C ₂ -C ₈ -dialdehydes are very particularly preferred. The aldehyde of component i) is very particularly preferably one or more compounds selected from the group consisting of glyoxal, butanedialdehyde, butenedialdehyde, glutardialdehyde, adipaldehyde and octanedialdehyde.

Most preferred is glutaric dialdehyde.

Preferred compounds of component ii) bearing NH ₂ groups are primary amines and/or amides. Aliphatic or aromatic C ₁ -C ₁₀ amines and/or amides are particularly preferred. The compound bearing NH ₂ groups is very particularly preferably selected from the group consisting of cyanamide, urea, melamine, urotropine, guanidine, formoguanamine, benzoguanamine, acetoguanamine, caprinoguanamine, isobutyroguanamine, acrylamide, benzamide, dicyandiamide (cyanoguanidine) and mixtures thereof.

The at least one compound bearing NH ₂ groups is very particularly preferably melamine or a mixture of melamine and urea.

Preferred salts of the acid groups of the condensation product are alkali metal, alkaline earth metal and ammonium salts, particularly preferably sodium and potassium salts.

Preferred acid groups are sulfonic acid groups or their salts.

component b4)

In the context of this application, vegetable tanning agents of component b4) are understood to mean, for example, tanning agents obtained from vegetable sources from the classes of condensed tanning agents or hydrolyzable tanning agents, e.g. B. chestnut extract, mimosa, tara or quebracho. Also suitable as vegetable tanning agents are those that can be obtained from plant sources such as algae, fruits, e.g. rhubarb, olives, parts of plants such as leaves, tree bark, roots, wood, possibly after chemical or enzymatic modification and/or by extractive methods .

additives

The additives listed below are preferred additives to which, however, the possible additives in the process according to the invention should not be restricted.

component c)

In addition to the condensation product of component a), in the process according to the invention for the production of semi-finished leather or fur products, at least one additive of component c) which differs from the condensation product of component a) and which is at least one emulsifier or its salt, to be present or not to be present.

In a preferred embodiment of the process according to the invention for the production of semi-finished leather or fur products, in addition to the condensation product of component a), at least one organic tanning agent of component b), which is different from the condensation product of component a), and at least one additive of Component c), which is at least one emulsifier or its salt, is present.

Examples of suitable emulsifiers are cationic, anionic, amphoteric and nonionic surfactants, which are preferably able to reduce the interfacial tension between an organic and an aqueous phase in such a way that an oil-in-water emulsion can form.

Preferred cationic emulsifiers are quaternary ammonium compounds, for example cetyltrimethylammonium bromide or chloride or benzyllauryldimethylammonium chloride.

Preferred anionic emulsifiers are soaps, metal soaps, organic soaps such as mono-, di- or triethanolamine oleate, stearate, diethylethanolamine oleate, stearate or 2-amino-2-methylpropan-1-ol stearate, sulfonated compounds such as sodium dodecyl sulfate or Turkish red oil, and sulfonated compounds such as sodium cetyl sulfonate .

Preferred amphoteric emulsifiers are phosphatides such as lecithins, various proteins such as gelatin or casein and the actual amphoteric surfactants.

Preferred nonionic emulsifiers are fatty alcohols such as lauryl, cetyl, stearyl or palmityl alcohol, partial fatty acid esters of polyhydric alcohols with saturated fatty acids such as glycerol monostearate, pentaerythritol monostearate, ethylene glycol monostearate or propylene glycol monostearate, partial fatty acid esters of polyhydric alcohols with unsaturated fatty acids such as glycerol monooleate, pentaerythritol monooleate, and also polyoxyethylene esters of fatty acids such as polyoxyethylene stearate, polymerization products of ethylene oxide and Propylene oxide on fatty alcohols such as fatty alcohol polyglycol ethers or fatty acids such as fatty acid ethoxylates.

Particularly preferred nonionic emulsifiers are at least one nonionic, ester group-containing, alkoxylated polyol having an HLB value of at least 13 (c1) and/or an alkyl glycoside (c2) and/or a nonionic ester group-free alkoxylated alcohol (c3).

component c1)

The preferred nonionic, ester group-containing, alkoxylated polyols of component c1) have an HLB value of 13 to 19, in particular 14 to 18, the HLB value being determined by the method according to Griffin, W.C.: Classification of surface active agents by HLB, J. Soc. cosmetics Chem. 1, 1949. Preferred compounds of component (c1) also have a water solubility at 20° C. of at least 10 g per liter, in particular at least 20 g per liter.

Preferred compounds of component c1) are those which can be obtained in a manner known per se from polyols by alkoxylation and partial esterification of the hydroxyl groups with a carboxylic acid. Suitable starting polyols which can be used as starter molecules are, for example, polyhydric (cyclo)aliphatic alcohols such as glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, polyols derived from mono- or polysaccharides, preferably with a molecular weight of 92 to 2000. Particularly preferred starter alcohols are polyols with 3 to 10 hydroxyl groups, especially glycerol and those with a sorbitan backbone, especially 1,4- or 1,5-sorbitan, preferably 1,4-sorbitan.

Preferred aqueous compositions are characterized in that the compound of component c1) is the reaction product of a polyol with at least one alkylene oxide having 2 to 6 carbon atoms, preferably in an amount of 10 to 60 molar equivalents, based on the polyol and thereafter Reaction with at least one carboxylic acid having 6 to 30 carbon atoms. The polyol used is preferably a polyol from the group consisting of glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, and polyols derived from mono- and polysaccharides, in particular sorbitol and polyols with a sorbitan backbone.

The compounds of component c1) are particularly preferably partially esterified sorbitan alkoxylates whose hydroxyl groups are esterified with carboxylic acids having a chain length of 6 to 30 carbon atoms before or preferably after the alkoxylation, with each hydroxyl group of the base polyol having an independent number of May have alkoxy units and per sorbitan unit on average 10 to 60 alkoxy units are present. The preferred esterified sorbitan alkoxylates have a statistical distribution of the alkoxy groups.

• X ein Sorbitanrest, insbesondere ein 1,4-Sorbitanrest ist und
• m für die Zahl 4 steht
• mit

Partially esterified alkoxylated sorbitan derivatives by reacting a sorbitan of the formula are preferred X-(OH)m wherein

• X is a sorbitan residue, in particular a 1,4-sorbitan residue and
• m stands for the number 4
• With

10 to 60 equivalents, per mole of sorbitan, preferably 10 to 40, particularly preferably 10 to 30 and very particularly preferably 15 to 25 equivalents of identical or different C2-C6-alkylene oxides, in particular C2- and / or C3-alkylene oxides, preferably ethylene oxide and with

1 to 3, preferably 0.8 to 1.2 equivalents, based on the sorbitan, of an aliphatic, optionally unsaturated carboxylic acid, preferably with a chain length of 6 to 30 carbon atoms, which is unsubstituted or substituted by hydroxyl groups, preferably straight-chain, in made in any order. The reaction with the alkylene oxide preferably takes place first and then the reaction with the carboxylic acid.

Preference is given to sorbitan polyoxyethylene monoesters which are alkoxylated with 10-60 mol ethylene oxide units per sorbitan unit and preferably have a 1,4-sorbitan backbone.

in denen
R für einen ggf. durch Hydroxylgruppen substituierten Alkyl- oder Alkenylrest der Carbonsäure steht und m, n, p und q unabhängig voneinander sind, statistische Werte sind und jeweils für eine Zahl von 0 bis 60 stehen, mit der Maßgabe, dass die Summe der Anzahl der Oxyethylen-Einheiten m+n+p+q von 10 bis 60, vorzugsweise 18 bis 22, insbesondere 20 ist.These preferably correspond to the following structural formulas,

in which
R is an optionally hydroxyl-substituted alkyl or alkenyl radical of the carboxylic acid and m, n, p and q are independent, statistical values and each represents a number from 0 to 60, with the proviso that the sum of the number of oxyethylene units m+n+p+q is from 10 to 60, preferably 18 to 22, especially 20.

Corresponding alkoxylated sorbitan diesters and mixtures thereof are also suitable.

Also suitable are alkoxylated sorbitan esters where one hydroxyl group of the sorbitan moiety, particularly in the formulas given above, is directly esterified with the carboxylic acid, i.e. where there is no alkylene oxide moiety between the sorbitan moiety and the carboxylic acid residue and the three are unacylated Hydroxyl groups are etherified with a correspondingly higher number of alkylene oxide units. Such compounds can be obtained, for example, by first esterifying the sorbitan with a carboxylic acid and then alkoxylating the product obtained, consisting of a mixture of the isomeric monoesters which, if there is an excess of carboxylic acid, can also contain mixtures of the isomeric diesters.

The alkylene oxide used for the alkoxylation of the sorbitan is preferably selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide. It is also possible for the sorbitan to be reacted with various of the alkylene oxides mentioned, e.g. ethylene oxide and propylene oxide, with sorbitan alkoxylates being able to be obtained which each have blocks of several units of one alkylene oxide, e.g. ethylene oxide, in addition to blocks of several units of another alkylene oxide, e.g., propylene oxide. The sorbitan alkoxylates particularly preferably contain ethylene oxide (EO) units, preferably exclusively. In such a case, the alkylene oxide used is particularly preferably ethylene oxide.

Furthermore, it is possible to obtain sorbitan alkoxylates in which the various alkylene oxides are incorporated randomly by reacting a sorbitan with various of the alkylene oxides mentioned, e.g. ethylene oxide and propylene oxide. The amounts of alkylene oxide used are preferably 10 to 60 moles of alkylene oxide per mole of sorbitan, preferably 10 to 40 moles, particularly preferably 10 to 30 moles and very particularly preferably 15 to 25 moles. A preferred alkylene oxide is ethylene oxide.

The carboxylic acids suitable for the esterification of the starting polyol, especially the sorbitan alkoxylate, are preferably saturated or unsaturated and linear or branched and can optionally be substituted by hydroxyl groups. The following carboxylic acids may be mentioned, for example: hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, Hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, octadecenoic acid (oleic acid), undecenoic acid. Decanoic acid, undecanoic acid, dodecanoic acid (lauric acid), tetradecanoic acid, hexadecanoic acid (palmitic acid) and octadecanoic acid (stearic acid), ricinoleic acid are particularly preferred. Dodecanoic acid (lauric acid), hexadecanoic acid (palmitic acid) and octadecanoic acid (stearic acid) and octadecenoic acid (oleic acid) are very particularly preferred.

Commercially available products can be used as compounds of component c1), for example sorbitan polyoxyethylene-(20) ^monolaurate (for example Polysorbate® 20 or ^Tween® 20 (Croda Oleochemicals) or ^Eumulgin® SML 20 (Cognis)), sorbitan polyoxyethylene (20) monopalmitate (e.g. Polysorbate ^® 40 or Tween ^® 40 (Croda Oleochemicals)), sorbitan polyoxyethylene (20) monostearate (e.g. Polysorbate ^® 60 or Tween ^® 60 (Croda Oleochemicals) or Eumulgin ^® SMS 20 (Cognis)), sorbitan polyoxyethylene (20) monooleate (e.g. Polysorbate ^® 80 or Tween ^® 80 (Croda Oleochemicals)).

Further preferred compounds of component c1) are, for example, alkoxylates of mono- and polyglycerol esters. Such alkoxylated (poly)glycerol esters are produced either by alkoxylating glycerol or a polyglycerol and subsequent esterification with a fatty acid or by esterifying the glycerol or polyglycerol with a fatty acid and subsequent alkoxylation. Alkoxylates of mono- and polyglycerol esters which have an HLB value of at least 13 and preferably have a water solubility at 20° C. of more than 10 g per liter are particularly suitable for the compositions according to the invention. Also suitable are alkoxylated glycerol esters or polyglycerol esters which are esterified with more than one carboxylic acid. Alkoxylated monoglycerol monoesters are particularly preferred.

_C.sub.2 to _C.sub.6 -alkylene oxides, particularly preferably ethylene oxide, are suitable for the alkoxylation. Alkoxylation with 10 to 100 alkylene oxide units, in particular with 20 to 60 alkylene oxide units, is preferred. The hydroxyl groups of the glycerol or of the polyglycerol independently of one another have on average a different number of alkylene oxide units.

Examples of particularly suitable alkoxylates are mono- and polyglycerol esters. mentioned: glycerol monostearate ethoxylates with an average of 15 to 30, in particular with an average of 20 EO units, glycerol monooleate ethoxylates with 20 to 40 EO units, diglycerol monostearate with 20 to 40 EO units, polyglycerol monostearate with 20 to 40 EO units Units, castor oil alkoxylates and hydrogenated castor oil alkoxylates, in short (hydrogenated) castor oil alkoxylates. It is in the latter to products by alkoxylation of castor oil or hydrogenated castor oil with alkylene oxides, in particular ethylene oxide and propylene oxide, are available, preference being given to those which have 20 to 100 alkylene oxide units per (hydrogenated) castor oil unit, preferably 20 to 60 ethylene oxide units per (hydrogenated) castor oil unit.

Corresponding glycerol-based compounds of components c1) are also available as commercial products, for example glycerol monostearate ethoxylate with an average of 20 EO units as ^Cutina® E 24 (Cognis), hydrogenated castor oil ethoxylate with an average of 40 EO units as ^Eumulgin® HRE 40 (Cognis).

component c2)

Preferred compounds of component c2) are, for example, alkyl monoglycosides, alkyl diglycosides, alkyl triglycosides and higher homologues, generally referred to here as alkyl glycosides, in particular monoglucosides, diglucosides, triglucosides, or higher homologues and mixtures thereof, whose hydroxyl groups are partially C ₆ -C ₁₈ -alkyl groups are substituted. Mixtures of mono-, di-, triglucosides and higher homologues with C ₆ -C ₁₈ -alkyl groups and a degree of polymerization (DP) of 1 to 5 are preferred. Alkyl glucosides whose alkyl groups have a chain length of 6 to 18 carbon atoms are particularly preferred , In particular 6 to 12 carbon atoms. Also preferred are alkyl glucosides whose alkyl groups have a chain length distribution or are mixtures of alkyl glucosides with different alkyl chains.

Other preferred compounds of component c2) are in the application WO 2012136565 A1 on p. 17, line 29 - p. 20, line 2.

component c3)

Preferred nonionic, ester-group-free alcohol alkoxylates of component c3) are polyether alcohols which are obtainable in a manner known per se by alkoxylating suitable starter molecules. For example, such are off EP-A-1647563 known. Any monohydric or polyhydric alcohols with a molecular weight of 88 to 438 can be used as starter molecules to produce the polyether alcohols.

Alkoxylates of aliphatic alcohols with a chain length of 5 to 30 carbon atoms and 1 to 25 alkoxy units are particularly preferred.

• R ein Alkylrest mit 5 bis 30 Kohlenstoffatomen ist, der eine Hauptkette mit 4 bis 29 Kohlenstoffatomen aufweist, die in der Kettenmitte mit mindestens einem C₁- bis C₁₀-Alkylrest verzweigt ist;
• das Alkylenoxid 2 bis 6 Kohlenstoffatome aufweist
• und
• der n ein Wert von 1 bis 25 ist.

Preference is given to using linear or branched, saturated or unsaturated alcohol alkoxylates which are obtained by reacting at least one alcohol ROH with n moles of at least one alkylene oxide per mole of alcohol ROH, wherein

• R is an alkyl group of 5 to 30 carbon atoms having a main chain of 4 to 29 carbon atoms which is mid-chain branched with at least one C ₁ to C ₁₀ alkyl group;
• the alkylene oxide has 2 to 6 carbon atoms
• and
• the n is a value from 1 to 25.

Other preferred compounds of component c3) are in the application WO 2012136565 A1 on p. 20, line 3 -p. 22, line 5.

component d)

In addition to the condensation product of component a), in the process according to the invention for the production of semi-finished leather or fur products, at least one additive of component d) which is different from the condensation product of component a) and which is the at least one carboxylic acid or salt thereof , to be present or not to be present.

Suitable compounds of component d) are, in particular, mono- or polycarboxylic acids, preferably hydroxypolycarboxylic acids. Examples which may be mentioned are: formic acid, acetic acid, oxalic acid, glyoxylic acid, malonic acid, lactic acid, tartaric acid, maleic acid, glutaric acid, phthalic acid, adipic acid, malic acid, succinic acid, citric acid, or polycarboxylic acids such as (co)polymers of (meth)acrylic acid, maleic acid, crotonic acid or Itaconic acid or derivatives thereof with optionally further monomers such as ethene, propene, styrene, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl vinyl ether, in particular those which have an average molar mass (weight average MW) of 500 to 100,000 g/mol, in particular 500 to 30000 g/mol.

Particularly preferred carboxylic acids or salts thereof in component d) are oxalic acid, succinic acid, glutaric acid or adipic acid, in particular at least one hydroxypolycarboxylic acid, preferably citric acid, tartaric acid or lactic acid or mixtures thereof.

component e)

In addition to the condensation product of component a), at least one additive of component e) which differs from the condensation product of component a) and which is selected from the groups of fatliquoring agents, fillers and/or buffering substances, may or may not be present.

Fatliquors are preferably substances based on biological, mineral or synthetic oils, which can be provided with hydrophilic groups to improve their usability in water, e.g. B. by complete or partial sulfation, sulfitation, carboxylation or phosphating.

Inert inorganic salts and organic polymers are preferred as fillers, e.g. B. sulfates such as sodium sulfate or calcium sulfate, talc, silicon oxide compounds, starch or lignin sulfonates.

Suitable buffer substances are to be understood as meaning those which, when added in a sufficient amount, are able to set and stabilize a pH range, in particular a pH range from 1 to 5, preferably 2.0 to 3.5. Mixtures of compounds of component d) and their salts are preferably suitable buffers for this purpose. Alkali metal salts, preferably sodium or potassium salts, are particularly suitable as preferred salts.

Examples of preferred dedusting agents are alkoxylates of aromatic compounds or polyethers or certain diesters. Specific examples include: ethoxylates, propoxylates or mixed polyethers based on EO/PO, with hydroquinone or phenol-styrene being mentioned as aromatic compounds, polyethylene glycol with an average molecular weight of 100 to 800, polypropylene glycol with an average molecular weight of 100 to 800, EO /PO mixed polyethers with an average molar mass of 100 to 800, monoalkyl ethers or dialkyl ethers of the abovementioned polyethers, where the alkyl radical can have 1 to 4 carbon atoms. Dedusting agents based on mineral oil are also suitable. Dedusting agents are preferably used in an amount of 0 to 5.0%, preferably 0.1 to 2.0%, based on the condensation product of component a).

Components a) to e) can be used separately or as a mixture in the process according to the invention.

In a preferred embodiment of the process according to the invention, the at least one tanning assistant of component b) is reacted with at least one of components c) to e) to form a solid, particulate material which is then used in the process according to the invention.

The solid, particulate material comprising the at least one tanning assistant of component b) and at least one of components c) to e) is particularly preferably obtained by spray-drying a mixture of these components.

Other preferred features of the solid, particulate material and its production are in the application WO 2012136565 A1 on page 2, line 30 - page 3, line 13 and on page 25, line 12 - page 33, line 12.

• 50 bis 100 Gew.-% eines Kondensationsproduktes der Komponente a), dessen Struktureinheiten abgeleitet sind von Phenolsulfonsäure, Dihydroxydiphenylsulfon und Formaldehyd,
• 0 bis 50 Gew.-% wenigstens eines organischen Gerbhilfsmittels der Komponente b), bevorzugt einer Carbamoylsulfonatgruppen-haltigen Verbindung (b1),
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenigstens eines Zusatzstoffes der Komponente c), der wenigstens ein Emulgator oder dessen Salz ist, insbesondere wenigstens ein nicht-ionisches, Estergruppen-haltiges, alkoxyliertes Polyol mit einem HLB-Wert von wenigstens 13 (c1) und/oder ein Alkylglycosid (c2) und /oder ein nichtionischer Estergruppen-freier alkoxylierter Alkohol (c3),
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenigstens eines Zusatzstoffes der Komponente d), der wenigstens eine Carbonsäure oder deren Salz ist, bevorzugt Oxalsäure, Bernsteinsäure, Glutarsäure oder Adipinsäure, insbesondere wenigstens eine Hydroxy-Polycarbonsäure, vorzugsweise Zitronensäure, Weinsäure oder Milchsäure oder Gemische daraus, und
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenigstens eines weiteren Zusatzstoffes der Komponente e), ausgewählt aus den Gruppen der Fettungsmittel, Füllstoffe und/oder Puffersubstanzen.

In a further embodiment, the method according to the invention is characterized in that hides or skins are treated in the presence of the following components, the percentages by weight being based on the sum of components a) to e):

• 50 to 100% by weight of a condensation product of component a), the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde,
• 0 to 50% by weight of at least one organic tanning assistant of component b), preferably a compound (b1) containing carbamoylsulfonate groups,
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one additive of component c), which is at least one emulsifier or its salt, in particular at least one nonionic, ester group-containing, alkoxylated polyol with an HLB value of at least 13 (c1) and/or an alkyl glycoside (c2) and/or a nonionic ester group-free alkoxylated alcohol (c3),
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one additive of component d), which is at least one carboxylic acid or a salt thereof, preferably oxalic acid, succinic acid, glutaric acid or adipic acid, in particular at least one hydroxypolycarboxylic acid, preferably citric acid, tartaric acid or lactic acid or mixtures thereof, and
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one further additive of component e), selected from the groups of fatliquors, fillers and/or buffer substances.

The process according to the invention is also suitable for the production of semi-finished leather or fur products containing chromium.

After the hides or skins have been treated with the condensation product of component a), the "pickling" process step then takes place. Pickling is preferably salt-free. A standard chrome tanning agent, preferably a basic chrome sulphate tanning agent with a basicity of 33%, is then added. After the addition results in Generally a pH between 2.0 and 3.0 and after adding a known basifying agent for chrome tanning, for example sodium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, magnesium carbonate, magnesium oxide, the pH is increased in order to fix the chrome tanning agent . At the end of the chrome tanning, the pH is between 3.5 and 4.5.

It is advantageous to use the pulverulent chrome tanning agent in the process according to the invention for the production of chromium-containing semi-finished leather or fur products in an amount of 1 to 10% by weight, based on the weight of the pelt. The chromium-containing semi-finished product obtained is then sammed and shaved as usual and can then also be retanned and advantageously used for the production of leather. With this procedure, a particularly high exhaustion of the chrome tanning agent is achieved and a reduction in the salt load in the waste water is achieved by eliminating the use of salt in the pickle. The wide range of applications of the method according to the invention is particularly advantageous.

In the particularly preferred embodiment, however, the method according to the invention is used for the production of wet white leather or fur. It is preferable to fix the condensation product of component a) with formic acid at the end of tanning. For this purpose, a pH of 3.0 to 5.0, preferably 4.0 to 5.0, is set with formic acid. Post-treatment with a customary preservative and addition of formic acid is particularly advantageous, with a pH of 3.0 to 4.0 preferably being set.

The invention also relates to the semi-finished leather or fur products, preferably wet white leather or furs, obtained by the process according to the invention.

The invention further relates to a process for producing leather or fur using the semi-finished leather or fur products obtained by the process for producing the semi-finished leather or fur products according to the invention.

This aforementioned process also includes the steps of retanning semi-finished leather or fur products with other substances that are common for the person skilled in the art and contribute to the optimization of the haptic and optical properties, for example in terms of color, fullness, softness and levelness.

• 50 bis 100 Gew.-% eines Kondensationsproduktes der Komponente a), dessen Struktureinheiten abgeleitet sind von Phenolsulfonsäure, Dihydroxydiphenylsulfon und Formaldehyd,
• 0 bis 50 Gew.-% wenigstens eines organischen Gerbhilfsmittels der Komponente b), bevorzugt einer Carbamoylsulfonatgruppen-haltigen Verbindung (b1),
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenigstens eines Zusatzstoffes der Komponente c), der wenigstens ein Emulgator oder dessen Salz ist, insbesondere wenigstens ein nicht-ionisches, Estergruppen-haltiges, alkoxyliertes Polyol mit einem HLB-Wert von wenigstens 13 (c1) und/oder ein Alkylglycosid (c2) und /oder ein nichtionischer Estergruppen-freier alkoxylierter Alkohol (c3),
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenisgstens eines Zusatzstoffes der Komponente d), der wenigstens eine Carbonsäure oder deren Salz ist, bevorzugt Oxalsäure, Bernsteinsäure, Glutarsäure oder Adipinsäure, insbesondere wenigstens eine Hydroxy-Polycarbonsäure, vorzugsweise Zitronensäure, Weinsäure oder Milchsäure oder Gemische daraus, und
• 0 bis 10 Gew.-%, bevorzugt 0 bis 5 Gew.-% wenigstens eines weiteren Zusatzstoffes der Komponente e), ausgewählt aus den Gruppen der Fettungsmittel, Füllstoffe und/oder Puffersubstanzen,

wobei die Angaben in Gew.-% auf die Summe der Komponenten a) bis e) bezogen sind.Furthermore, a mixture A is described containing

• 50 to 100% by weight of a condensation product of component a), the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenylsulfone and formaldehyde,
• 0 to 50% by weight of at least one organic tanning assistant of component b), preferably a compound (b1) containing carbamoylsulfonate groups,
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one additive of component c), which is at least one emulsifier or its salt, in particular at least one nonionic, ester group-containing, alkoxylated polyol with an HLB value of at least 13 (c1) and/or an alkyl glycoside (c2) and/or a nonionic ester group-free alkoxylated alcohol (c3),
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one additive of component d), which is at least one carboxylic acid or salt thereof, preferably oxalic acid, succinic acid, glutaric acid or adipic acid, in particular at least one hydroxypolycarboxylic acid, preferably citric acid, tartaric acid or lactic acid or mixtures thereof, and
• 0 to 10% by weight, preferably 0 to 5% by weight, of at least one further additive of component e), selected from the groups of fatliquoring agents, fillers and/or buffer substances,

where the percentages by weight are based on the sum of components a) to e).

In a preferred embodiment of the process according to the invention for producing leather or fur using the semifinished leather or fur products obtained by the process according to the invention for producing the semifinished leather or fur products, the above mixture A is used.

The above mixture A can be used alone or in combination with other customary components used for retanning in the process according to the invention for the production of leathers or furs. The above mixture can be used before, during or after the other customary components used for retanning.

Customary components that can be used for retanning are known per se. Examples of suitable components that can be used for retanning are (co)polymers of acrylic acid and its derivatives, which are present as aqueous dispersions (eg Lubritan SP, TG, and Leukotan 1084, 1093 from LANXESS), aqueous dispersions of polyisobutenes, hydrophobic modified polyamide carboxylic acids (e.g. Levotan L, Levotan LB), polyether carboxylic acid (e.g. Levotan C01), graft copolymers of acrylic acid or acrylic acid derivatives on polysaccharides, proteinaceous materials, hydrolysates of polysaccharides, in particular starch, hydrolysates of proteins, in particular collagen or mixtures thereof (e.g. Levotan X- biomer), Dispersions based on ionic polyurethanes, syntans based on polycondensates of aromatic compounds with formaldehyde such as Tanigan BN, Tanigan 3LN, Tanigan VR, Tanigan OS, Tanigan UW, Tanigan HO, resin tanning agents such as Retingan R7, Retingan ZF, dyes, dyeing auxiliaries such as Baykanol SL , dispersing agents such as Tanigan PR, fatliquoring agents, for example those based on natural and synthetic oils and fats, waterproofing agents such as emulsions based on polysiloxanes or formulations based on paraffinic hydrocarbons or hydrophobic polymers. These products are commercially available and known per se to those skilled in the art.

The leathers or furs obtained by the process according to the invention for the production of leathers or furs are also a subject of the present invention. The outstanding properties of the leather or fur semi-finished products according to the invention were also transferred to the leather or furs obtained.

The use of mixture A according to the invention for treating hides or skins, in particular pelt material, is also described.

The use of mixture A according to the invention for treating semi-finished leather or fur products, preferably wet white leather or furs, is also described.

In the following examples, the present invention is documented by way of example without limitation.

examples A) Materials (LANXESS products)

• Tanigan BN: pulverförmiges Kondensationsprodukt auf Basis von Naphthalinsulfonsäure, Dihydroxydiphenylsulfon und Formaldehyd.
• Tanigan 3LN: pulverförmiger Weissgerbstoff auf Basis von sulfoniertem Phenol, einer aminofunktionellen Verbindung und Formaldehyd.
• Tanigan HO: pulverförmiges Kondensationsprodukt auf Basis von sulfonierten Aromaten, sulfoniertem Phenol und Formaldehyd.
• Tanigan UW: pulverförmiges Kondensationsprodukt auf Basis von sulfonierten Aromaten, sulfoniertem Phenol und Formaldehyd.
• TANIGAN CF liq: Kondensationsprodukt auf Basis von Naphthalinsulfonsäuren, sulfoniertem Phenol und Formaldehyd.

Organic tanning agents:

• Tanigan BN: Powdered condensation product based on naphthalene sulfonic acid, dihydroxydiphenyl sulfone and formaldehyde.
• Tanigan 3LN: powdered white tanning agent based on sulfonated phenol, an amino-functional compound and formaldehyde.
• Tanigan HO: Powdered condensation product based on sulfonated aromatics, sulfonated phenol and formaldehyde.
• Tanigan UW: Powdered condensation product based on sulfonated aromatics, sulfonated phenol and formaldehyde.
• TANIGAN CF liq: Condensation product based on naphthalene sulfonic acids, sulfonated phenol and formaldehyde.

• CHROMOSAL B: basisches Chromsulfat mit einer Basizität von 33% und einem Chromgehalt von ca. 26%, berechnet als Chromoxid Cr₂O₃.
• BLANCOROL BA: spezielles Basifizierungsmittel für die Chromgerbung

Inorganic components:

• CHROMOSAL B: basic chromium sulphate with a basicity of 33% and a chromium content of approx. 26%, calculated as chromium oxide Cr ₂ O ₃ .
• BLANCOROL BA: special basifying agent for chrome tanning

• PELTEC AN 90: nichtionischer Emulgator.
• LEVAZYM AF: wässrige Enzym-Formulierung für die Beize.
• PELTEC ADN: Entfettungs- und Netzmittel.
• PREVENTOL U-Tec G: Konservierungsmittel zur Behandlung von Wet White- und Wet Blue-Ledern und -Pelzen.
• TANIGAN PAK: pulverförmiger Neutralisationgerbstoff.
• BAYKANOL Licker SL: Fettungsmittel.
• LEVOTAN C-01: anionischer Polyaddukt-Nachgerbstoff mit Carboxylgruppen.
• LEUKOTAN 1084: hochmolekulare Polyacrylat-Dispersion (Leukotan: Warenzeichen von Dow Chemical).
• LEVOTAN LB: wässrige Dispersion einer modifizierten Polyamidcarbonsäure.
• Mimosa XS : Vegetabilgerbstoff (Mimosa).
• BAYGENAL Beige L-NGR: beige Farbstoff-Formulierung.
• BAYGENAL Brown CRE: braune Farbstoff-Formulierung.
• BAYGENAL Black TDE: schwarze Farbstoff-Formulierung.
• LEVOTAN W: Hydrophobiermittel auf Basis einer Silicon-Mikroemulsion.
• RETINGAN R 12: Harzgerbstoff mit selektiver Füllwirkung auf Basis eines Formaldehyd-Kondensats.

Other additives:

• PELTEC AN 90: non-ionic emulsifier.
• LEVAZYM AF: aqueous enzyme formulation for stain.
• PELTEC ADN: degreasing and wetting agent.
• PREVENTOL U-Tec G: Preservative for the treatment of wet white and wet blue leather and fur.
• TANIGAN PAK: neutralizing tanning agent in powder form.
• BAYKANOL Licker SL: fatliquor.
• LEVOTAN C-01: anionic polyadduct retanning agent with carboxyl groups.
• LEUKOTAN 1084: high molecular weight polyacrylate dispersion (Leukotan: trademark of Dow Chemical).
• LEVOTAN LB: aqueous dispersion of a modified polyamide carboxylic acid.
• Mimosa XS : Vegetable tanning agent (Mimosa).
• BAYGENAL Beige L-NGR: beige dye formulation.
• BAYGENAL Brown CRE: brown dye formulation.
• BAYGENAL Black TDE: black dye formulation.
• LEVOTAN W: Hydrophobing agent based on a silicone microemulsion.
• RETINGAN R 12: Resin tanning agent with selective filling effect based on a formaldehyde condensate.

B) Preparation of the condensation product of component a) Example 1: Aqueous solution of the condensation product of component a)

173.3 g (2.17 mol) of sodium hydroxide solution (50% by weight) are metered into an initial charge of 150.0 g of water, resulting in a temperature of about 60.degree. At 60° C., 252.7 g (0.94 mol) of phenolsulfonic acid (65% by weight) are metered in over 30 minutes. The reaction mixture is kept at 80° C. by cooling during the metering time.

Then an aqueous suspension (52.6% by weight) containing 680.0 g (2.72 mol) of dihydroxydiphenyl sulfone (100% by weight) which is prepared by condensing phenolsulfonic acid with phenol and suspending the reaction product in water/diluted Caustic soda is produced, added at 90 ° C in 50 minutes. Stirring is continued at 90° C. for 1 hour.

256.0 g (2.56 mol) of aqueous formaldehyde solution (30% by weight) are then metered in at 90-95° C. in 45 minutes. The temperature is then raised to 105°C where the condensation reaction begins and the temperature rises to about 115°C. It is condensed at 114-116° C. and a pressure of about 1 bar for 6 hours.

It is then cooled to 90°C. 2.5 g Rongalit C are added and stirred for 30 minutes. The aqueous solution has a solids content of approx. 50% by weight.

The solids content is then adjusted by adding water, as is the pH. Solids content: 25% by weight, pH (neat): 8.5

Example 2 Condensation product of component a) as a solid

The aqueous solution from example 1 with a solids content of about 50% by weight is spray-dried at 180.degree. A light powder is obtained.

Water content: 7.2% by weight, pH (5 g / 50 g water): 8.3

C) Formulations of components b) to e) Example 3 Formulation of components b1), c1) and d)

To a solution of 95.5 g sorbitan polyethylene glycol (20) monododecanoate (e.g. Eumulgin SML 20 (Cognis) or Tween 20 (Croda)) alkoxylated with a total of 20 ethylene oxide units per sorbitan unit (HLB 16.7 ), in 3199.5 g water and 4524.8 g sodium bisulfite solution (NaHSO ₃ 38-40% in water) are metered in at 25 ° C and a pH of 4.36 with stirring 1358.3 g hexamethylene diisocyanate within 40 minutes , wherein the temperature of the reaction mixture is adjusted to 50°C within. The pH is 5.62. Then 70.3 g of citric acid (anhydrous) dissolved in 70.3 g of water are added.

The mixture is stirred at 50° C. for a further 1 hour, during which time the reaction mixture becomes clear. It is then cooled to 25° C. within 2 hours. The mixture is stirred at room temperature (20-23° C.) for a further 1 hour. The pH of the solution is 4.67. Then 211.3 g of citric acid (anhydrous) dissolved in 211.3 g of water are added and the mixture is stirred for 15 minutes. The concentration is adjusted by adding 258.7 g of water. A clear 35.0% solution with a pH of 3.11 is obtained.

500 g of the solution were then spray dried. A white powder was obtained.

Water content: 1.5%, pH (in aqueous solution with 10% solids content): 3.3

Example 4 Formulation of components b1), c1), d) and e)

8.75 g of sodium sulfate were added to 500 g of the 35% solution from Example 3 and stirred at 40.degree. The solution obtained was then spray-dried.

A white powder was obtained.

Water content: 1.0%, pH (in aqueous solution with 10% solids content): 3.5

Example 5 Formulation of components b1), b2), c1), d) and e)

To a solution of 95.5 g sorbitan polyethylene glycol (20) monododecanoate (e.g. Eumulgin SML 20 (Cognis) or Tween 20 (Croda)) alkoxylated with a total of 20 ethylene oxide units per sorbitan unit (HLB 16.7 ), in 3199.5 g water and 4524.8 g Sodium bisulfite solution (NaHSO ₃ , 38-40% in water) are metered in at 25° C. and a pH of 4.36 with stirring, 1358.3 g of hexamethylene diisocyanate within 40 minutes, the temperature of the reaction mixture being adjusted to 50° C. within this time becomes. The pH is 5.62. Then 70.3 g of citric acid (anhydrous) dissolved in 70.3 g of water are added.

The mixture is stirred at 50° C. for a further 1 hour, during which time the reaction mixture becomes clear. It is then cooled to 25° C. within 2 hours. The mixture is stirred at room temperature (20-23° C.) for a further 1 hour. The pH of the solution is 4.67. Then 211.3 g of citric acid (anhydrous) dissolved in 211.3 g of water are added and the mixture is stirred for 15 minutes. The concentration is adjusted by adding 258.7 g of water. A clear, 35.0% solution having a pH of 3.11 is obtained.

5000 g of a 35% solution of the compound containing carbamoyl sulfonate groups described above and 5000 g of a 50% solution of a syntan of ditolyl ether sulfonic acid, 4,4′-dihydroxydiphenyl sulfone and formaldehyde are fed into a spray dryer with a disc atomizer using a pump, with the inlet temperature was set at 165°C. The starting temperature was between 70 and 80°C. Caking in the dryer was not observed.

A finely divided, almost colorless powder with a bulk density of 562 g per 1000 ml was obtained, which had a dry residue of 99.27% (IR dryer, 120° C., standard drying, drying to constant weight). The dust-free product obtained had a particle size of 5.0 μm to 300 μm and dissolved in water very quickly without clumping. A solution of 5 g powder in 50 ml water had a pH of 3.40.

Example 6:

80 g of the product from Example 2 was mixed with 20 g of the product from Example 4.

Example 7:

80 g of the product from Example 2 was mixed with 20 g of the product from Example 3.

Example 8:

90 g of the product from Example 2 was mixed with 10 g of the product from Example 4.

Example 9:

90 g of the product from Example 2 was mixed with 10 g of the product from Example 3.

Example 10:

80 g of the product from Example 2 was mixed with 20 g of the product from Example 5.

Example 11:

90 g of the product from Example 2 was mixed with 10 g of the product from Example 5.

Example 12:

• Vorlage 235 g Wasser, 264 g Natronlauge (50%) (3,296 mol), 395 g Phenolsulfonsäure (65%) (1,476 mol), wässrige Suspension enthaltend 720,8 g (2,880 mol) Dihydroxydiphenylsulfon (100%), 291 g Formaldehyd (31,4%) (3,046 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 2,23 : 1,00 : 1,95 : 2,06.
• Die erhaltene wässrige Lösung wurde mit 1750 g Wasser und 21 g Schwefelsäure 50% auf einen Feststoffgehalt von 25,3 Gew.-% (pH-Wert: 8,0) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Template 235 g water, 264 g sodium hydroxide solution (50%) (3.296 mol), 395 g phenolsulfonic acid (65%) (1.476 mol), aqueous suspension containing 720.8 g (2.880 mol) dihydroxydiphenyl sulfone (100%), 291 g formaldehyde ( 31.4%) (3.046 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 2.23:1.00:1.95:2.06.
• The aqueous solution obtained was adjusted to a solids content of 25.3% by weight (pH: 8.0) with 1750 g of water and 21 g of 50% sulfuric acid.

Example 13:

• Vorlage 289 g Wasser, 325 g Natronlauge (50%) (4,067 mol), 485 g Phenolsulfonsäure (65%) (1,810 mol), wässrige Suspension enthaltend 623,6 g (2,492 mol) Dihydroxydiphenylsulfon (100%), 288 g Formaldehyd (31,4%) (3,009 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 2,25 : 1,00 : 1,38 : 1,66.
• Die erhaltene wässrige Lösung wurde mit 1900 g Wasser und 57 g Schwefelsäure 50% auf einen Feststoffgehalt von 25,5 Gew.-% (pH-Wert: 7,9) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Initially 289 g water, 325 g sodium hydroxide solution (50%) (4.067 mol), 485 g phenolsulfonic acid (65%) (1.810 mol), aqueous suspension containing 623.6 g (2.492 mol) dihydroxydiphenyl sulfone (100%), 288 g formaldehyde ( 31.4%) (3.009 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 2.25:1.00:1.38:1.66.
• The aqueous solution obtained was adjusted to a solids content of 25.5% by weight (pH: 7.9) with 1900 g of water and 57 g of 50% sulfuric acid.

Example 14:

• Vorlage 226 g Wasser, 170 g Natronlauge (50%) (2,123 mol), 379 g Phenolsulfonsäure (65%) (1,416 mol), wässrige Suspension enthaltend 738,0 g (2,949 mol) Dihydroxydiphenylsulfon (100%), 289 g Formaldehyd (31,4%) (3,020 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 1,50 : 1,00 : 2,08 : 2,13.
• Die erhaltene wässrige Lösung wurde mit 2150 g Wasser auf einen Feststoffgehalt von 23,6 Gew.-% (pH-Wert: 7,3) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Template 226 g water, 170 g sodium hydroxide solution (50%) (2.123 mol), 379 g phenolsulfonic acid (65%) (1.416 mol), aqueous suspension containing 738.0 g (2.949 mol) dihydroxydiphenyl sulfone (100%), 289 g formaldehyde ( 31.4%) (3.020 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 1.50:1.00:2.08:2.13.
• The aqueous solution obtained was adjusted to a solids content of 23.6% by weight (pH value: 7.3) with 2150 g of water.

Example 15:

• Vorlage 374 g Wasser, 167 g Natronlauge (50%) (2,082 mol), 628 g Phenolsulfonsäure (65%) (2,342 mol), wässrige Suspension enthaltend 586,1 g (2,342 mol) Dihydroxydiphenylsulfon (100%), 319 g Formaldehyd (31,4%) (3,331 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 1,29 : 1,00 : 1,00 : 1,42.
• Die erhaltene wässrige Lösung wurde mit 1800 g Wasser auf einen Feststoffgehalt von 27,3 Gew.-% (pH-Wert: 6,7) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Original 374 g water, 167 g sodium hydroxide solution (50%) (2.082 mol), 628 g phenolsulfonic acid (65%) (2.342 mol), aqueous suspension containing 586.1 g (2.342 mol) dihydroxydiphenyl sulfone (100%), 319 g formaldehyde ( 31.4%) (3.331 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 1.29:1.00:1.00:1.42.
• The aqueous solution obtained was adjusted to a solids content of 27.3% by weight (pH value: 6.7) with 1800 g of water.

Example 16:

• Vorlage 174 g Wasser, 201 g Natronlauge (50%) (2,518 mol), 292 g Phenolsulfonsäure (65%) (1,091 mol), wässrige Suspension enthaltend 790,1 g (3,157 mol) Dihydroxydiphenylsulfon (100%), 325 g Formaldehyd (31,4%) (3,398 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 2,31 : 1,00 : 2,89 : 3,11.
• Die erhaltene wässrige Lösung wurde mit 1900 g Wasser auf einen Feststoffgehalt von 24,9 Gew.-% (pH-Wert: 7,9) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Initially 174 g water, 201 g sodium hydroxide solution (50%) (2.518 mol), 292 g phenolsulfonic acid (65%) (1.091 mol), aqueous suspension containing 790.1 g (3.157 mol) dihydroxydiphenyl sulfone (100%), 325 g formaldehyde ( 31.4%) (3.398 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 2.31:1.00:2.89:3.11.
• The aqueous solution obtained was adjusted to a solids content of 24.9% by weight (pH value: 7.9) with 1900 g of water.

Example 17:

• Vorlage 174 g Wasser, 201 g Natronlauge (50%) (2,518 mol), 292 g Phenolsulfonsäure (65%) (1,091 mol), wässrige Suspension enthaltend 790,1 g (3,157 mol) Dihydroxydiphenylsulfon (100%), 366 g Formaldehyd (31,4%) (3,823 mol). Molverhältnis Natriumhydroxid : Phenolsulfonsäure : Dihydroxydiphenylsulfon : Formaldehyd = 2,31 : 1,00 : 2,89 : 3,50.
• Die erhaltene wässrige Lösung wurde mit 1840 g Wasser auf einen Feststoffgehalt von 25,5 Gew.-% (pH-Wert: 7,8) eingestellt.

Example 1 was repeated, but the amounts used were changed as follows:

• Initially 174 g water, 201 g sodium hydroxide solution (50%) (2.518 mol), 292 g phenolsulfonic acid (65%) (1.091 mol), aqueous suspension containing 790.1 g (3.157 mol) dihydroxydiphenyl sulfone (100%), 366 g formaldehyde ( 31.4%) (3.823 moles). Molar ratio sodium hydroxide: phenolsulfonic acid: dihydroxydiphenylsulfone: formaldehyde = 2.31:1.00:2.89:3.50.
• The aqueous solution obtained was adjusted to a solids content of 25.5% by weight (pH value: 7.8) with 1840 g of water.

D) Process according to the invention for producing semi-finished leather products

After liming, split and weighed pelts (cattle) are used as the starting material, the thickness of which is approx. 2.2-2.5 mm. All of the following quantities of chemicals are based on this reference weight (pelt weight).

The process starts with a washing process with 30°C warm water for about 10 minutes. After the liquor change, a 30-minute preliminary decalcification begins, which must be nitrogen-free. For this purpose, approx. 0.2% by weight of a 90% surfactant (e.g. PELTEC AN 90) is used together with 0.2% by weight of sodium bisulfite to prevent the formation of hydrogen sulphide and 0.15% by weight of a deliming agent (e.g. PELTEC DL EXP 2031, from LANXESS). After 30 minutes the pH value has dropped from approx. 12.5 to pH 9. The actual deliming now follows, which consists of adding two different products: 1.0% by weight of the deliming agent (eg PELTEC DLP EXP 2025, from LANXESS), and 0.2% by weight of a second deliming agent (e.g. PELTEC DL EXP 2031, from LANXESS) added. The purpose of this deliming is to convert the lime, which was introduced into the skin during liming to increase the pH and during the opening of the skin, back into water-soluble salts and wash it out of the pelt. Depending on the thickness of the pelt, this process takes between 90 and 180 minutes. The pH value is checked by dripping phenolphthalein onto the cut edge of the freshly cut pelt. The section should be colorless. If a pink zone is still visible, the running time must be extended.

Then it is floated with water at 35°C and pickled for about 45 minutes by adding a nitrogen-free pickling agent. This serves to break down non-leather proteins and increases the softness of the resulting leather. The ideal pH value should be between pH 8.0 and 8.5. This is followed by repeated washing with 20°C cold water to wash out the dissolved lime and to stop the enzyme's pickling activity.

Up to this point, all tanning systems run more or less the same. In most known tanning systems, a pick (mixture of salt and acid) then follows, which lowers the pH value to approx. 3.0 and thus prepares the pelt for the absorption of the tanning agents.

In the following embodiment of the method according to the invention, this process step of the pimple is dispensed with.

Tanning is started at a pH of about 8 with a fresh liquor quantity of 30-50% by weight. Optionally, a fatliquor (eg EUREKA 975 ES) can be added to increase softness. Afterwards or at the same time, 5% by weight of the condensation product of component a) (from example 1 or 2, the liquid product from example 1 was used with the same solid content as the powdered product from example 2) is added and the drum is heated for approx. 5 hours at approx 14 rpm run. This is the penetration phase, which is indicated by an indicator (iron (III) chloride) can also be checked. The pH value remains stable at approx. 8. In this range, the product still shows a slight tanning effect, which is reflected in the low shrinkage temperature (Ts) of approx. 65°C. After penetration, the condensation product of component a) is fixed with formic acid and its tanning effect is activated. To avoid mold infestation, a fungicide is added (eg PREVENTOL U-Tec G from LANXESS). After a pH balance of approx. 4.0 - 4.5 has been reached, the leather is washed. By activating the tanning effect, the shrinkage temperature (Ts) rises to over 70°C, which is perfectly adequate for the subsequent mechanical work steps. A further addition of a drying agent for better dewatering and handling on the machines, as is customary in similar tanning processes, can be dispensed with in the process according to the invention.

Table 1 shows the process steps of the process according to the invention for the production of semi-finished leather products (the percentages by weight relate to the pelt weight). Table 1 Product: Amount [% by weight] running time [min] Remarks Water 30°C 200 10 Fleet off Water 32°C 30 PELTEC AN 90 0.2 sodium bisulfite 0.2 + PELTEC DL EXP2031 0.15 30 pH 9.0 + PELTEC DLP EXP 2025 1.0 PELTEC DL EXP 2031 0.2 75 pH 8.3 + Water 35°C 50 LEVAZYME AF 0.15 45 check section with phenolphthalein: colorless pH 8.2 Fleet off Water 20°C 150 10 Fleet off Water 20°C 150 10 Fleet off Water 25°C 50 EUREKA 975 ES 1.0 Product from example 1 or 2 (amount used based on solids) 5.0 300 pH 8.1 Ts: 65-67°C + formic acid (1 : 5) 1.0 PREVENTOL U-Tec G 0.15 60 pH 5.0 + formic acid (1 : 5) 1.0 60 pH ~ 4.0 Fleet off Ts: 70 - 73°C Water 20°C 200 10 Fleet off

According to the process according to the invention, the semi-finished leather products are stored on a trestle, sammed and seamed.

The liquid product from Example 1 was used with the same solid content as the powdered product from Example 2. The amount of this product used is based on the amount of solids in the products used in each case from the other production examples, based in each case on the weight of the pelt.

The products from Preparation Examples 6-11 were used analogously to the products from Examples 1 and 2 in the process according to the invention.

The corresponding experimental data of the application examples are summarized in Table 2 below. Table 2 Application example no product Amount [% by weight] Pimple running time [min] pH end of term Ts [°C] 1 example 1 5 no 300 8.1 73 2 example 2 5 no 300 8.1 72 3 example 1 5 Yes 300 5 72 4 example 2 5 Yes 300 5 73 5 Example 6 5 no 300 8.1 73 6 Example 7 5 no 300 8.1 71 7 example 8 5 no 300 8.1 72 8th example 9 5 no 300 8.1 72 9 Example 10 5 no 300 8.1 71 10 Example 11 5 no 300 8.1 71 11 (comparison) Tanigan BN 7.5 no 300 8.1 61 / 65 12 (comparison) Tanigan 3LN 7.5 no 300 8.1 59 / 63 13 (compare Tanigan HO 7.5 no 300 8.1 60 14 (comparison) Tanigan UW 7.5 no 300 8.1 62 15 (comparison) Tanigan BN 7.5 Yes 300 5 61 16 (comparison) Tanigan 3LN 7.5 Yes 300 5 59 17 (compare Tanigan HO 7.5 Yes 300 5 60 18 (comparison) Tanigan UW 7.5 Yes 300 5 62

The semi-finished leather products produced with the products of Examples 1, 2, 6-11 show no grain and can be sammed very easily. Their foldability is significantly improved compared to the semi-finished leather products from Comparative Examples 11-18 because, unlike the semi-finished leather products from Comparative Examples 11-18, they are not sticky. The semi-finished leather products according to Comparative Examples 12 and 16 were also pelt-like.

The production of semi-finished leather products described above was repeated, with any changes in the implementation being shown in Table 3 (the % by weight relates to the pelt weight).

In this case, 20% by weight of the product from Example 1 or 5% by weight of the product from Example 2 or approx. 20% by weight of the aqueous solutions of the condensation products (component a)) from Examples 12 to 17 admitted. The amounts of condensation products (component a)) used given in Tables 3 and 4 were correspondingly converted to the solids content, are based on the pelt weight and were therefore identical in all experiments with the same solids content. Table 3 Application example no product off Amount [% by weight] Pimple running time [min] 19 Example 12 5 no 600 20 Example 13 5 no 600 21 Example 14 5 no 600 22 Example 15 5 no 600 23 Example 16 5 no 600 24 Example 17 5 no 600 25 example 2 5 no 600 26 example 1 5 no 600

The results are compiled in Table 4 below. The 1st check of the pH value and shrinkage temperature Ts was carried out after a running time of 600 minutes, the 2nd check after acidification with formic acid. Table 4 Application example no product off Amount [% by weight] 1.Control pH value 1.Control TS [°C] 2.Control pH value 2.Control Ts [°C] 19 Example 12 5 8.2 60 3.8 70 20 Example 13 5 8.1 59 3.9 70 21 Example 14 5 7.9 64 3.6 70 22 Example 15 5 7.7 61 3.5 70 23 Example 16 5 8.2 62 3.7 72 24 Example 17 5 8.3 63 3.6 73 25 example 2 5 8.3 63 3.5 74 26 example 1 5 8.2 64 3.4 74

The semi-finished leather products produced by this process using the products from Examples 12 to 17, Example 1 and Example 2 show no grain and can be sammed easily. The foldability is best for the products of Examples 13, 15 and 16 (no sticking to the roller). Good folding results were also achieved in the other examples.

Use Example 27 Production of a chromium-containing semi-finished leather product according to the invention

The production of semi-finished leather products described above was repeated, with any changes in the implementation being shown in Table 5 (the % by weight relates to the pelt weight).

4% by weight of the condensation product a) from example 2 were added. The keg is run for 3 hours. The pH value remains stable at around 8.

After a pH equilibrium of approx. 3.5 to 4.5 had been reached after the addition of PREVENTOL U-Tec G, 0.9% by weight of sulfuric acid was added, with a pH value of approx of 3.3 resulted. The advantage of this procedure is that a salt-free pimple (without the use of table salt) is possible as a result of the pretreatment with the product according to the invention according to Example 2.

Then 6.0% by weight of a chrome tanning agent with a basicity of 33% (eg Chromosal B) was added. The barrel was allowed to run for 60 minutes, and a pH of 2.6 was established. Then 0.55% by weight of a basifying agent (eg Blancorol BA) was added. The keg was then run for 720 minutes (overnight automatic). After that, the pH was 3.9. Table 5 Crowd [%] product Amount [kg] runtime [minutes] Remarks 200.00 Water 30°C 12,000 10 Fleet off 30.00 Water 32°C 1,800 0.20 PELTEC AN 90 0.012 0.20 sodium bisulfite 0.012 0.15 PELTEC DL EXP 2031 0.009 30 pH 10.6 1.50 PELTEC DLP EXP 2025 0.090 0.20 PELTEC DL EXP 2031 0.012 0.000 75 pH 8.2 50.00 Water 35°C 3,000 PP: colorless 0.15 LEVAZYME AF 0.009 45 pH 8.1 0.000 Fleet off 200.00 Water 20°C 12,000 15 0.000 Fleet off 40.00 Water 20°C 2,400 1.00 EUREKA 975ES 0.060 4.00 Product from example 1 0.240 180 pH 8.0 0.000 0.70 formic acid 0.042 0.15 PREVENTOL U-Tec G 0.009 30 pH 4.3 0.90 sulfuric acid 0.054 90 pH 3.3 (bromocresol green: yellow) 6.00 CHROMOSAL B 0.360 60 pH 2.6 0.55 BLANCOROL BA 0.033 720 Automatic overnight (12 hours) pH 3.9 Temp: 42°C

The semi-finished leather products were unloaded, stored on a trestle, wilted and seamed. The processing during wilting and folding was very good. The color of the chromium-containing semi-finished product is somewhat more bluish than the comparison without chromium tanning agent. Improved liquor exhaustion compared to normal chrome tanning without treatment with the product from Example 1 was observed. The surface of the grain shows a very fine grain structure.

This example shows that semi-finished products containing chromium, wet blue leather, can also be produced by the process according to the invention.

E) Process according to the invention for the production of leather

The semi-finished leather products according to the invention obtained in the application examples described above from application examples 1, 2 and comparative examples 11, 12 (8.80 kg, shaved thickness 1.0 mm) were retanned after shaving in accordance with a standard procedure known to those skilled in the art, with the product according to Example 2 was used. Furthermore, the semi-finished leather products were dyed, greased and processed into crust leather. A typical retanning recipe for the production of automotive crust leather was used.

The leathers are then finished in the usual way and evaluated according to their intended use. Table 6 shows the process steps of the process according to the invention for producing leather (the percentages by weight are based on the weight of the semi-finished leather product). Table 6 process Amount [% by weight] Products running time [min] pH remark Addition of the skins To wash 200.00 Water 35°C 1:6 0.30 Peltec ADN 10 4.30 Fleet off neutralization 50.00 Water 30°C 0.30 sodium bicarbonate 1:8 2.00 TANIGAN PAK retanning 3.00 BAYKANOL Licker SL 1:3 30 5.20 2.00 LEVOTAN C-01 1:3 5 4.00 LEUKOTAN 1084 1:3 10 3.00 LEVOTAN LB 1:3 10 5.40 8.00 TANIGAN BN ) 3.00 Mimosa XS ) 5.00 TANIGAN CF liq) sodium bicarbonate 1:8 60 4.90 2.00 BAYKANOL Licker SL 6.00 Product according to example 2 3.00 Mimosa XS ) 1:8 coloring 0.40 BAYGENAL Beige L-NGR 0.05 BAYGENAL Brown CRE 0.01 BAYGENAL Black TDE 180 5.10 penetration 50.00 water 50°C 1:8 10 Heating 50°C 3.00 BAYKANOL Licker SL ) 1:5 60 overnight automatic. 5.30 1.00 formic acid 1:5 30 4.30 Fleet off fat licker 100.00 water 50°C 2.00 LEVOTAN W ) 1:8 7.00 BAYKANOL Licker SL ) 1:5 60 4.50 4.00 RETINGAN R 12 30 5.10 2.50 formic acid 1:5 40 3.70 0.50 formic acid 1:5 20 3.50 Fleet off 3.55 To wash 300.00 water 50°C 10 Fleet off To wash 300.00 Water 20°C 10 empty barrel

Mechanical operations such as stretching out, vacuum drying at 40° C./1 min, hanging drying, conditioning, staking and milling were carried out on the leathers obtained using the process according to the invention.

The overall assessment of the leather obtained according to the invention is as follows: Table 7 mission Semi-finished product from application example 11 Semi-finished product from application example 12 Semi-finished product from application example 1 Semi-finished product from application example 2 ts ¹ 61°C 59°C 73°C 72°C scar pull ¹ no no no no wilting ¹ 3 4 2 (best) 2 (best) foldability ¹ 3 (sticky) 4 (very sticky) 2 (barely) 1 (best) fill ² 2 3 2 2 softness ² 3 4 2 2 millability ² 2 3 1 1 ¹ : The properties were determined on the corresponding semi-finished products;
² : The properties were determined on the corresponding leathers; Overall assessment: 1: very good, to 5: unsatisfactory.

Leathers according to the invention, which were obtained from the semi-finished leather products from application examples 1 and 2, are to be rated as particularly advantageous. It should be emphasized that a significantly smaller amount of tanning agent was used in application examples 1 to 10 than in comparative examples 11-18. On the other hand, when the amount of tanning agent used is reduced in the comparative examples, pelt-like materials are obtained.

Although the leather according to Application Example 11 gives good millability and fullness, the foldability was poor and the Ts were very low.

The leather according to application example 12 has a poor shaving result and a low Ts. The crust properties such as fullness, softness and millability also received a significantly poorer rating. This test shows that leather with the most advantageous properties was obtained from the leather semi-finished products produced according to the invention.

The semi-finished leather products obtained from Application Examples 19 to 26, which were shaved to a thickness of 1.1 mm, were retanned under the conditions described in Table 6. The mechanical work was carried out as usual: stretching out, vacuum drying for 1 minute at 40°C, then hanging drying, Conditioning, cleats and milling. After milling, the chrome-free crust leathers obtained met the requirements for automobile leathers.

The examples according to the invention show the range of application of the process and show that the wet white leather can be produced without pimples and that the condensation products of component a) according to the invention can therefore contribute to reducing the waste water load in tanneries.

Claims (13)

1. Process for producing semi-finished leather or fur products, characterized in that hides or skins are treated in the presence of a component a) condensation product, the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenyl sulfone and formaldehyde, at a pH of 6.5 - 8.5, preferably 7 - 8.
2. Process according to Claim 1, characterized in that the process is conducted without a process step of pickling.
3. Process according to Claim 1 or 2, characterized in that the structural units of the component a) condensation product derived from phenolsulfonic acid, dihydroxydiphenyl sulfone and formaldehyde are present in a ratio of 1:(1-10):(1.4-7.7), preferably 1:(1-5):(1.4-4.2), particularly preferably 1: (2-4):(2.1-3.5).
4. Process according to any of Claims 1 to 3, characterized in that the component a) condensation product is used as a solid or in an aqueous solution.
5. Process according to any of Claims 1 to 4, characterized in that the process is a process for producing wet white leathers or furs.
6. Process according to any of Claims 1 to 5, characterized in that in addition to the component a) condensation product there is present at least one component b) organic tanning auxiliary which differs from the component a) condensation product, wherein the component a) condensation product and the at least one organic tanning auxiliary b) are preferably present in a ratio of 99:1 to 50:50, particularly preferably in a ratio of 95:5 to 70:30.
7. Process according to any of Claims 1 to 6, characterized in that in addition to the component a) condensation product there is present at least one component c) additive which differs from the component a) condensation product and is at least one emulsifier or salt thereof.
8. Process according to any of Claims 1 to 7, characterized in that in addition to the component a) condensation product there is present at least one component d) additive which differs from the component a) condensation product and is at least one carboxylic acid or salt thereof.
9. Process according to any of Claims 1 to 8, characterized in that the hides or skins are treated in the presence of the following components:

   - 50 to 100% by weight of a component a) condensation product, the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenyl sulfone and formaldehyde,

   - 0 to 50% by weight of at least one component b) organic tanning auxiliary, preferably carbamoylsulfonate group-containing compound (b1),

   - 0 to 10% by weight, preferably 0 to 5% by weight of at least one component c) additive which is at least one emulsifier or salt thereof, more preferably at least one nonionic alkoxylated polyol comprising ester groups and having an HLB value of at least 13 (c1) and/or alkylglycoside (c2) and/or nonionic alkoxylated alcohol free from ester groups (c3),

   - 0 to 10% by weight, preferably 0 to 5% by weight of at least one component d) additive which is at least one carboxylic acid or salt thereof, preferably oxalic acid, succinic acid, glutaric acid or adipic acid, especially at least one hydroxy polycarboxylic acid, preferably citric acid, tartaric acid or lactic acid or mixtures thereof, and

   - 0 to 10% by weight, preferably 0 to 5% by weight of at least one further component e) additive selected from the groups of fatliquoring agents, fillers and/or buffers,

   wherein the indications in % by weight (weight per cent) are based on the sum total of components a) to e).
10. Semi-finished leather or fur products, preferably wet white leathers or furs, produced by a process according to any of Claims 1 to 9.
11. Process for producing leathers or furs using the semi-finished leather or fur products, preferably wet white leathers or furs, according to Claim 10.
12. Process according to Claim 11, characterized in that the process employs a mixture A comprising

    - 50 to 100% by weight of a component a) condensation product, the structural units of which are derived from phenolsulfonic acid, dihydroxydiphenyl sulfone and formaldehyde,

    - 0 to 50% by weight of at least one component b) organic tanning auxiliary, preferably carbamoylsulfonate group-containing compound (b1),

    - 0 to 10% by weight, preferably 0 to 5% by weight of at least one component c) additive which is at least one emulsifier or salt thereof, more preferably at least one nonionic alkoxylated polyol comprising ester groups and having an HLB value of at least 13 (c1) and/or alkylglycoside (c2) and/or nonionic alkoxylated alcohol free from ester groups (c3),

    - 0 to 10% by weight, preferably 0 to 5% by weight of at least one component d) additive which is at least one carboxylic acid or salt thereof, preferably oxalic acid, succinic acid, glutaric acid or adipic acid, especially at least one hydroxy polycarboxylic acid, preferably citric acid, tartaric acid or lactic acid or mixtures thereof, and

    - 0 to 10% by weight, preferably 0 to 5% by weight of at least one further component e) additive selected from the groups of fatliquoring agents, fillers and/or buffers,

    wherein the % by weight are based on the sum total of components a) to e).
13. Leathers or furs produced by a process according to Claim 11 or 12.